The GPRS or universal mobile telecommunications system (UMTS) is an evolution of the global system for mobile communications (GSM) standard to provide packet switched data services to GSM mobile stations. Packet-switched data services are used for transmitting chunks of data or for data transfers of an intermittent or bursty nature. Typical applications for 3GPP packet service include Internet browsing, wireless e-mail, video streaming, and credit card processing, etc. used by human users.
Organizations both private & government that are Local & Global are looking for new and innovative ways to manage their business & operations at an optimum cost structure. As the cost of connectivity starts to drop precipitously, they are looking to take advantage of huge efficiency gains through access to data for processing and analysis in an optimized way, which previously was only available through costly human intervention.
These new applications and markets start to emerge that take advantage of ubiquitous cellular coverage. Even though the underlying radio technology continues to evolve from 2, 2.5, 3G and now LTE, new innovation is being developed to take advantage of this infrastructure in the form of smart devices and sensors that are creating new market opportunities for Mobile Network Operators (MNO's). Cellular networks are ideal in connecting millions of data collecting devices to the processing infrastructure. The opportunity to connect millions and even billions of devices is creating an exciting market opportunity commonly defined as M2M.
However, as MNO's look to seize this new market opportunity, there are many challenges in adopting the same practices and architecture that were designed for a very different human consumer market model. The cost structure is fundamentally different, the relationship with the Enterprise is fundamentally different and the impact on the network from non-human devices is fundamentally different.
Most machine to machine offerings currently in the market treat the cellular network as a transport pipe. While this approach is simple and can be deployed using existing cellular infrastructure, it ignores the fact that machine type communication needs are inherently different than those for a human subscriber. Furthermore, lots of machine type communication is more signaling intensive than data intensive; i.e. the amount of data that is communicated between the device and the network is often times very small and there are many signaling exchanges to establish the data channel between the device and the network. Furthermore, a number of MTC devices can be a lot bigger than that of single user subscribers, e.g. a smart meter deployed in a county could be millions. As the number of connected devices goes up, the network would succumb to signaling overload and possible other forms of congestion, especially in the radio network.
FIG. 1 is a block diagram illustrating signaling overhead of typical machine to machine type communications over GPRS network architecture. Referring to FIG. 1, machine type devices 101 are communicatively coupled to a UMTS mobile network 110. For example, machine type device 101 is coupled to the mobile network 110 via a 3G Radio access network through e.g. nodeB or NB and radio network controller (RNC) 102, a serving GPRS support node (SGSN) for 3G network or serving gateway (S-GW) for LTE network 103 and a gateway GPRS support node (GGSN) for 3G network or packet data network (PDN-GW) 104 for LTE network. In order for the MTC device 101 to communicate to a MTC application server 106 located in other networks such as Internet and/or Enterprise premise, machine type devices 101 go through UMTS mobile network 110, which relay communications between a machine type UE 101 and a destination (e.g. Enterprise server 106).
For the UE to establish relationship with the network, there are lots of signaling messages exchanged between the UE and the network. For MTC services, most of the communications are initiated by the MTC application server 106 which sends the command to the MTC devices 101. In order to save the radio and core network resources and to save the battery usage of the devices, the UMTS mobile network puts the device into “idle” mode. When a device enters idle mode, it removes all the radio associations and frees up that radio resource and only listens to a common broadcasting channel for paging. Based on a statistics of machine to machine communications, there will be billions of connected devices in a few years and this will result in significant increase in amount of signaling due to paging.
When a MTC application server 106 sends has a command to send to a device 101, the UMTS mobile network 110 first needs to establish the signaling and bearer connection before it can send anything from the network. This process starts by the application server 106 sends the multiple commands for multiple devices 111 to the GGSN or P-GW 104. The GGSN or P-GW 104 sends multiple commands for multiple devices 112 to the SGSN or S-GW/MME 103 to wake up one or more devices from the idle mode. The SGSN or MME 103 sends multiple queries 113 to the HSS 105 to check the status and the location of the devices. Then the SGSN or MME 103 sends multiple paging messages 114 to the RNCs 102 for the devices. When the device is in idle mode, the network does not know which RNC 102 the device is located at, so the SGSN 103 has to send the paging message to all the RNCs 102 in the same routing area. This means if there are three RNCs 102 in one routing area, SGSN 103 sends three paging request messages (one for each RNC) for each device. If the command was for thousand devices in certain routing area, this means there will be 3000 paging requests over the air. Radio spectrum is an expensive and rare resource for the mobile operators and supporting the MTC devices could put lots of burden on the radio resources especially as the number of MTC devices grow exponentially, to millions and billions.